import pygame
import sys
import random

# 游戏框
SCREEN_X = 600
SCREEN_Y = 600


# 蛇
# 点以25为属性
class Snake(object):
    # 初始化各种需要的属性（开始默认向右，身体5块）
    def __init__(self):
        self.dirction = pygame.K_RIGHT
        self.body = []
        for x in range(5):
            self.addnode()

    # 在前面加块
    def addnode(self):
        left, top = (0, 0)
        if self.body:
            left, top = (self.body[0].left, self.body[0].top)
        node = pygame.Rect(left, top, 25, 25)
        if self.dirction == pygame.K_LEFT:
            node.left -= 25
        elif self.dirction == pygame.K_RIGHT:
            node.left += 25
        elif self.dirction == pygame.K_UP:
            node.top -= 25
        elif self.dirction == pygame.K_DOWN:
            node.top += 25
        self.body.insert(0, node)

    # 删除最后一个块
    def delnode(self):
        self.body.pop()

    # 死亡判断
    def isdead(self):
        # 撞墙
        if self.body[0].x not in range(SCREEN_X):
            return True
        if self.body[0].y not in range(SCREEN_Y):
            return True
        # 撞自己
        if self.body[0] in self.body[1:]:
            return True
        return False

    # 移动
    def move(self):
        self.addnode()
        self.delnode()

    # 改变方向，但是左右上下不能逆向改变
    def changedirection(self, curkey):
        LR = [pygame.K_LEFT, pygame.K_RIGHT]
        UD = [pygame.K_UP, pygame.K_DOWN]
        if curkey in LR + UD:
            if (curkey in LR) and (self.dirction in LR):
                return
            if (curkey in UD) and (self.dirction in UD):
                return
            self.dirction = curkey


# 食物放置移除
class Food:
    def __init__(self):
        self.rect = pygame.Rect(-25, 0, 25, 25)

    def remove(self):
        self.rect.x = -25

    def set(self):
        if self.rect.x == -25:
            allpos = []
            for pos in range(25, SCREEN_X - 25, 25):
                allpos.append(pos)
                self.rect.left = random.choice(allpos)
                self.rect.top = random.choice(allpos)
                print(self.rect)


def show_text(screen, pos, text, color, font_bold=False, font_size=60, font_italic=False):
    # 获取系统字体，设置大小
    cur_font = pygame.font.SysFont('宋体', font_size)
    # 是否加粗
    cur_font.set_bold(font_bold)
    # 是否斜体
    cur_font.set_italic(font_italic)
    # 内容
    text_fmt = cur_font.render(text, 1, color)
    # 绘制
    screen.blit(text_fmt, pos)


def main():
    pygame.init()
    screen_size = (SCREEN_X, SCREEN_Y)
    screen = pygame.display.set_mode(screen_size)
    pygame.display.set_caption('Snake')
    clock = pygame.time.Clock()
    scores = 0
    isdead = False

    # 蛇/食物
    snake = Snake()
    food = Food()

    while True:
        for event in pygame.event.get():
            if event.type == pygame.QUIT:
                sys.exit()
            if event.type == pygame.KEYDOWN:
                pressed_keys = pygame.key.get_pressed()
                if pressed_keys.count(1) > 1:
                    continue
                snake.changedirection(event.key)
                if event.key == pygame.K_SPACE and isdead:
                    return main()

        screen.fill((255, 255, 255))

        # 画蛇身
        if not isdead:
            scores += 1
            snake.move()
        for rect in snake.body:
            pygame.draw.rect(screen, (20, 220, 39), rect, 0)

        # 显示死亡
        isdead = snake.isdead()
        if isdead:
            show_text(screen, (100, 200), 'You Dead!', (227, 29, 18), False, 100)
            show_text(screen, (150, 260), 'Press space to try again...', (0, 0, 22), False, 30)

        # 食物处理/吃到+50，当食物rect与蛇头重合，吃掉->Snake增加一个Node
        if food.rect == snake.body[0]:
            scores += 50
            food.remove()
            snake.addnode()

        # 食物投递
        food.set()
        pygame.draw.rect(screen, (136, 0, 21), food.rect, 0)
        # 显示分数
        show_text(screen, (50, 500), 'Scores:' + str(scores), (223, 223, 223))
        pygame.display.update()
        clock.tick(5)


if __name__ == '__main__':
    main()
